The invention relates to an over-center hinge for cabinet doors, having two links hinged at one end to a door member and at the other end to a wall member in the form of an elongated bearing arm, in the manner of a quadruple joint, the said links being movable through a dead-center position in the movement from the closed position to the open position, on the first side of which it is urged by the tension of a resilient element in the closing direction, and beyond which it is urged by the tension of the resilient element in the opening direction, the resilient element disposed in the front, door-end portion of the bearing arm engaging with one end a projection at the bearing arm end a lever arm which is so directed away from the pivot axis that it is biased by the resilient element in the hinge-closed position to a movement in the closing direction, and in the hinge-open position to a movement in the opening direction.
Such over-center hinges, which are urged by spring tension into two stable end positions, have the advantage that a door mounted on a cabinet with such a hinge does not stop in intermediate positions, i.e., with the door ajar, and cannot be damaged by drawers in the cabinet, such as drawers for pots, supplies, or swing-out kitchen appliances in kitchen cabinets. An over-center hinge of this kind is known (German Offenlegungsschrift No. 21 17 828) in which a V-shaped leaf or wire spring is used to produce the spring tension, the spring being so disposed that the apex of the V-shaped spring passes around the pivot pin provided on the bearing arm side of the outer hinge link facing away from the bearing wall, while the free end of one of the spring legs engages a projection in the bearing-arm end of the other hinge link, while the second spring leg thrusts directly or indirectly against the bearing arm. On account of the limited space available, the production of a sufficiently great spring force by such V-shaped springs is difficult, and, especially when hairpin springs formed from spring steel wire are coiled about several times at the apex are involved, their installation is complicated. Consequently, over-center hinges of this kind have not found a market.